Antivirus

1. ANTI VIRAL DRUGS
DR.MINU BABY

2. ANTIVIRAL DRUGS-CLASSIFICATION
Anti-Herpes Virus Drugs
Anti-Influenza Virus Drugs
Anti-Hepatitis Virus Drugs
Anti-Retroviral Drugs

3. Anti-Herpes Virus Drugs
• Acyclovir ,
• Valacyclovir ,
• Famciclovir
• Penciclovir ,
• Ganciclovir
• Cidofovir ,
• Foscarnet,
• Fomivirsen
• Structural analogues of nucleosides
• Activated to triphosphate forms
• Competitive inhibition of viral thymidione
kinase and DNA/RNA polymerase

5. ANTI-INFLUENZA DRUGS

6. DRUGS FOR HEPATITIS
Are drugs which are effective against
 Hepatitis B Virus(HBV)-DNA virus
 Hepatitus C Virus (HCV)-RNA virus

7. DRUGS FOR HEPATITIS B
Hepatitis B Virus is a DNA virus
It integrates into chromosomal DNA
Causes permanent infection
It is unable to eradicate the viral antigen from the body
GOAL OF TREATMENT
 Suppress viral replication.
To reduce its inflammatory & hepatocyte damaging process.
 Prevent progression of hepatic disease & complications like cirrhosis and
hepatic carcinoma

8. DRUGS FOR HEPATITIS B
LAMIVUDINE
ENTECAVIR
ADEFOVIR DIPIVOXIL
TENOFOVIR
TELBIVUDINE
INTERFERON
Not to be stopped suddenly as it can result in acute exacerbation of
hepatitis
To be continued till 6 months after seroconversion to minimize
reactivation

10. LAMIVUDINE
A cytosine analogue
Effective for both HIV & Hep B
Mechanism OF ACTION
Inhibit HBV DNA Polymerase
Also get incorporated in the viral DNA and causes chain
termination
Inhibit HIV reverse transcriptase

11. LAMIVUDINE
USES
Hepatitis B: Chronic hepatitis
HIV
DISADVANTAGES
Resistance
Tenofovir & Adefovir preferred in Lamivudine resistant cases
ADVERSE EFFECTS:
Headache,nausea,anorexia,abdominal pain,rashes
Pancreatitis,neuropathy  Rare

12. TENOFOVIR
Nucleotide analogue
Active against HIV & Hepatitis B
Is used as disoproxil ester PRODRUG
better Oral absorption
better viral entry

13. TENOFOVIR
Mechanism of Action
Nucleotide analogue
Tenofovir undergoes diphosphorylation by cellular kinase
Tenofovir diphosphate inhibits HBV DNA polymerase
It also gets incorporated in the viral DNA to cause chain termination
Inhibits HIV Reverse Transcriptase enzyme

14. TENOFOVIR
ADR:
GIT:Nausea,flatulence,loose stools,pain abdomen
Renal: proximal tubular disease
Slight increase in creatinine,acute/chronic renal disease
Fanconi Syndrome
USES
DOC for Hepatitis B – active even for lamivudine resistant cases
HIV

15. ENTECAVIR
Guanosine nucleoside analogue
Currently the first line drug for treatment of Chronic Hepatitis B
MOA :
Inhibits HBV DNA polymerase
Need to be taken in empty stomach ,food decreases oral
bioavailability
Long acting,half life is 128-148 hrs
Well tolerated,mild dyspepsia,disturbed sleep
Lactic acidosis in decompensated cirrhosis

16. Adefovir Dipivoxil
Prodrug of Adefovir
Adefovir  adenosine analogue
 MOA:Competitive inhibition of HBV DNA Polymerase
USES:Chronic Hepatitis B
Effective in Lamivudine resistant cases
Effective in patients with concomitant HIV infection
ADR:Nephrotoxicity
Flu syndrome,Sore throat

17. TELBIVUDINE
Newer anti-HBV drug
Thymidine analogue
MOA:Inhibits HBV DNA polymerase
Adavantages
Long acting
Orally effective
Faster & more complete suppression of HBV DNA titre
Disadvantages
Resistance
ADR: Well tolerated
Serum amylase may rise

18. DRUGS FOR HEPATITIS C
RIBAVIRIN
INTERFERON
NEWER DRUGS
i.NS5B Polymerase Inhibitor: Sofosbuvir
ii.NS3/4A Protease Inhibitor: Simepravir
iii.NS5A Inhibitors: Daclatasvir
Ledipasvir
Velpatasvir

19. INTERFERONS (IFN)
Interferons are cytokines produced by host cells in response to viral
infections
Three types of Interferons : IFN α, β, γ
Antiviral action  IFN α
Only IFN α2A & INF α2B are produced by recombinant technology &
are used clinically

20. Interferons bind to receptors(JAK-STAT tyrosine
kinase receptors)
Induces expression of interferon induced
proteins
Inhibit viral replication at multiple steps
:penetration, synthesis of viral mRNA and
viral proteins, release of progeny virus
INTERFERONS-MECHANISM OF ACTION

21. Interferon Alfa
No oral BA- polypeptide
s/c or im
Pegylated Interferons:
Obtined by attachment of IFN to polyethylene glycol (PEG)
molecules – pegylation
Increase duration of action
Enable once-weekly dosing
Enhanced clinical effiacy

22. Interferon α - USES
1.Chronic Hepatitis B
2.Chronic Hepatitis C
3.AIDS related Kaposi sarcoma
4.Condyloma Acuminata:caused by papilloma virus
Treated with topical podophyllin
Intralesional interferon in resistant cases
5.Herpes infection:IFN my be added to acyclovir in
immunocompromised patients
6.Hematological Malignancy:CML,Follicular lymphoma,Cutaneous T cell
Lymphoma,Multiple Myeloma

23. IFN-ADVERSE EFFECTS
IFN cause frequent & distressing adverse effects
IV infusion  Flu like symptoms
Thyroid dysfunction
Neurotoxicity , bone marrow toxicity,alopecia
Reversible Liver & kidney damage
Hypotension,transient arrhythmias
Alopecia
May impair fertility
Autoimmune diseases
Depression

24. RIBAVIRIN
A broad spectrum antiviral drug
Spectrum: HCV, Influenza A & B
Respiratory syncytial virus
MOA :Inhibits GTP synthesis& viral RNA synthesis
Long t1/2>10days,accumulates in body on daily dosing

25. RIBAVIRIN
USE: Chronic Hepatitis C , Influenza, Measles,
RSV-nebulised Ribavirin
NIPAH VIRUS
ADR: Dose dependent Hemolytic anemia,
Bone marrow supression
Cough,Dyspnoea,bronchospasm on nebulization
Teratogenicity

26. NEWER DRUGS FOR HEPATITIS C
NOVEL DIRECTLY ACTING AGENTS
They target NONSTRUCTURAL VIRAL PROTEINSreplication
Used in combination:Development of resistance
Advantages
-Better viral response
-Shorter duration of treatment
-Less toxic
-Delayed onset of resistance
Disadvantages
-More drug interactions

27. NON-STRUCTURAL PROTEINS

29. NS5B Polymerase Inhibitor:SOFOSBUVIR
It is a uridine analogue
Prodrug
Inhibits NS5B (HCV RNA polymerase )
PHARMACOKINETICS
Oral bioavailability is 80%improved with fatty meal
It is a substrate of Pgp efflux transporter should not be used with Pgp
inducers like Phenytoin, Rifampicin
ADR: Fatigue,pain abdomen,joint pain,anemia
Sever bradycardia if used with Amiodarone

30. NS3/4A PROTEASE Inhibitor:SIMEPRAVIR
Mechanism of Action
 NS3/4A protein helps to form functional viral polypepetides
 InhiBItion of this protein blocks viral replication
Pharmacokinetics
Orally effectiveabsorption increases when taken with meals
Metabolised by CYP3A4
Substrate for Pgp
USES:Chronic Hepatitis C
Given as Simepravir –Sofosbuvir combination for 12-24weeks
ADR:Photosensitivity,Rashes,dyspnea
DRUG INTERACTIONS

31. NS5A INHIBITORS
NS5A is a multifunctional protein essential for viral replication
I.DACLATASVIR
II.LEDIPASVIR
III.VALPATASVIR
Features
Used as combination therapy with SOFOSBUVIR
Metabolisd by CYP
Substrates of Pgp DRUG INTERACTIONS
Needs gastric acidity for
absorption

32. Drugs for Corona virus-COVID-19
Remdesivir
Baricitinib
Tocilizumab
Sotrovimab
Casirivimab + Imdevimab
Immune-based therapy: Convalescent plasma

33. THANK YOU